The present invention is directed to windows for x-rays, electrons, ions, etc., particularly to windows for high output x-ray tubes and particle/electron accelerators, and more particularly to a cooled window capable of simultaneously supporting pressure differentials and dissipating thermal loads with negligible attenuation of the beam passing there through.
There are many applications that require windows for x-rays, electrons or ions, such as high output x-ray tubes and particle or electron accelerators. One example is a window into a beam dump for high energy electrons from accelerators. Another example is a window that provides a vacuum-tight barrier to prevent leakage of atmospheric gases into a sealed tube that is used to produce x-rays. These types of applications induce significant thermal load on the window, as well as producing a pressure differential across the window.
The most general commercial application is in high output x-ray tubes used, for example, in helical computed tomography. As an example of these various applications, U.S. Pat. No. 5,128,977 issued Jul. 7, 1992 to M. Danos describes a configuration for an enhanced output x-ray tube in which the accelerated electrons are impinged onto a rotating anode at an angle of about 10.degree. to the anode surface, which is in contrast to the more common angle of 80.degree.-90.degree. , and such proportedly leads to a significant increase in the number of x-rays emitted. Unfortunately, the Danos configuration causes scattered electrons to impinge on the tube window causing melting thereof. Danos proposes two approaches to managing this difficulty: 1) locating the window out of line with the highest intensity of scattered electrons, and 2) deflecting the electrons with a magnetic field. By locating the window out of line with the scattered electron, x-ray intensity is compromised, and deflecting the electrons requires space to accommodate the magnet and beam dump within the tube.
Thus, there is a need for a window capable of withstanding the thermal load and pressure differential imposed thereon by applications involving high output x-rays tube, as well as particle and electron accelerators. That need if satisfied by the cooled window of this invention that offers good structural integrity and very high capacity for removal of the heat deposited by x-rays, electrons, or ions, and is accomplished while offering minimum attenuation of the desired beam.